Vertical continuous reactor and process for liquid epoxy resin

ABSTRACT

A vertical reactor system having a plurality of substantially vertically aligned reaction compartments one on top of the other, the reactant materials (and catalyst and solvent, if desired), flowable from a first top compartment through intermediate compartments, if any, to a bottom compartment from which a desired product of a reaction of the reactant materials is withdrawn, the compartments having inlets for the addition of additional reactants, catalysts, or solvents and outlets for withdrawing by-products, vapors, and water from any compartment, and processes for producing products using such a system. In one embodiment the product is a liquid epoxy resin. Stirring impellers may be provided in any compartment. A liquid seal may be provided on a shaft for the impellers and, in one embodiment the seals in each compartment may be elevated above the liquid in the compartments.

CROSS REFERENCE TO RELATED APPLICATION

This is a divisional of application Ser. No., 07/643,877 filed Jan. 18,1991, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to vertical continuous reactors; method of theiruse; and in one aspect to methods and apparatuses for producing epoxyresins, particularly a vertical continuous epoxy resin reactor andprocesses using it for producing epoxy resins.

2. Background of the Invention

Epoxy resins' superior toughness, chemical resistance, heat resistance,adhesion and electrical properties have contributed to their wide use inelectrical and structural applications and in protective coatings. Anepoxy group (1,2-epoxide or oxirane), a three-membered cyclic ethergroup, characterizes the epoxy resins. A curing agent reacts with thesemonomers or prepolymers to produce high performance thermosettingplastics.

A common form of epoxy resins are produced by well known processes suchas the reaction of dihydric phenols and epihalohydrin. In one suchprocess the epihalohydrin and dihydric phenol react in the presence of acatalyst to produce a halohydrin-containing resin intermediate which isthen reacted with a basic acting material, e.g. sodium hydroxide.Treatment of the resulting reaction mixture, such as by water-washing,removes residual catalyst and salt, producing a liquid epoxy resin.

Various dihydric phenols are employed; e.g. hydroquinone, resorcinol,catechol, and bisphenols. Suitable epihalohydrins which can be employedherein include, for example, epichlorohydrin, epibromohydrin,epiiodohydrin, methylepichlorohydrin, methylepibromohydrin,methyiepiiodohydrin, mixtures thereof and the like. Suitable catalystsinclude, for example, quaternary ammonium compounds, quaternaryphosphonium compounds, sulfonium compounds and the like.

Suitable quaternary ammonium catalysts include, for example, tetramethylammonium chloride, benzyl trimethyl ammonium chloride, triethanolammonium chloride, tetraethanol ammonium hydroxide, dodecyldimethylbenzyl ammonium naphthenate and the like. Suitable quaternaryphosphonium catalysts include, for example, those quaternary phosphoniumcompounds disclosed in U.S. Pat. Nos. 3,948,855, 3,477,990 and 3,341,580and Canadian 858,648 all of which are incorporated herein by reference.Other catalysts are ethyl triphenyl phosphonium iodide, ethyl triphenylphosphonium bicarbonate, ethyl triphenyl phosphonium acetate.acetic acidcomplex, benzyl triphenyl phosphonium chloride, tetrabutyl phosphoniumchloride, benzyl trimethyl ammonium chloride mixtures thereof and thelike. Suitable sulfonium catalysts include thiourea catalysts such as,for example, tetramethyl thiourea; N,N'-dimethyl thiourea; N,N'-diphenylthiourea; mixtures thereof and the like as well as thiodiethanon andother sulfonium precursors.

Also suitable as catalysts are the basic ion exchange resins such as,for example, DOWEX MSA-1, DOWEX 11, DOWEX SBR, mixtures thereof and thelike.

Specific processes for producing epoxy resins are described in theseU.S. Pat. Nos.; 4,313,886; 2,986,551; 3,069,434; 2,840,541; 3,221,032;4,017,523; 4,751,280; and 4,008,133; and in various foreign references,including Great Britain 2,095,679; West Germany 2,909,706 and 2,745,150;East Germany 218,767 and 213,226; and Czechoslovakia 212,856 and210,447. Known processes for producing liquid epoxy resins frombisphenol-A and ephichlorohydrin are either continuous or discontinuousprocessing operating in the presences of an alkali metal hydroxide inquantities of 2 moles, or about 2 moles, for every mole of bisphenol-A.

In a typical discontinuous process, a concentrated aqueous solution ofalkali metal hydroxide is fed to a solution of bisphenol-A inepichlorohydrin at atmospheric or slightly lower than atmosphericpressure. The temperature is controlled to continuously distill thewater introduced with the alkali metal hydroxide as an azeotropicmixture with the epichlorohydrin. After completion of the addition ofthe solution of alkali metal hydroxide, all the water is removed, theunreacted epichlorohydrin is recovered by distillation at pressureslower than atmospheric, and the alkali metal chloride, a sub-product ofthe reaction is separated by dissolving in water. Liquid epoxy resinsobtained in such a process have a high viscosity, an undesirable color,and because of their relatively high chlorine content, are not suitablefor various applications. Liquid epoxy resins made this way can have aresidual chlorine content of the order of 0.5-0.8% by weight.

Several method of producing liquid epoxy resins by a continuous process,by effecting the reaction of the bisphenol-A with the epichlorohydrin ina number of individual reactors installed in series are well known inthe art. In such processes, the bisphenol-A and the epichlorohydrin arecontinuously fed to a first reactor, while the alkali metal hydroxide inaqueous solution is introduced into each reactor up to a maximumquantity equal, or about equal to 2 moles for every mole of bisphenol-A.The reaction products are discharged continuously from the last reactorand are subjected to decantation to separate the liquid epoxy resin fromthe water and the alkali metal chloride which is a sub-product of thereaction.

In various conventional processes, the reaction is carried out in thepresence of oxygenated organic substances of alcoholic or ketonicnature. The presence of extraneous substances in these procedures cancause a decrease in the purity of the resin produced, and the reactivesubstances such as the alcohols or the ketones can give rise tosecondary reactions with formation of various sub-products. The addedsubstances are eventually separated from the liquid epoxy resin, and arepurified before recycling them to the reaction. The liquid epoxy resinis separated from the water and the alkali metal halide which is asub-product of the reaction.

The difficulty and the lack of spontaneity in the separation of liquidepoxy compounds from water or aqueous saline solutions, is well known.To facilitate this separation, substances capable of varying theinterface tension or the density have been used in the art; but theaddition of extraneous substances to the system causes a decrease in thepurity of the resin and the removal of these substances often proves tobe very difficult. However, when operating without these extraneoussubstances, lengthy periods of decantation at elevated temperature arenecessary causing undesirable secondary reactions.

Other processes in which an efficient reactor system would be usefulinclude processes for producing epihalohydrins and other chemistriesrequiring rapid separation of a vapor product from a liquid reactionmedia or a vapor by-product from a liquid reaction product.

There has long been a need for an effective and efficient continuousvertical reactor and methods of its use. There has long been a need foran effective and efficient continuous process for producing liquid epoxyresins. There has long been a need for apparatus for use in such aprocess. There has long been a need for a continuous process for theproduction of liquid epoxy resins in which reaction by-products may beremoved at various stages in the process. There has long been a need fora continuous process for the production of liquid epoxy resins in whichcatalysts and reactants can be added in a staged manner to minimizeyield losses to undesirable side reactions.

SUMMARY OF THE PRESENT INVENTION

the present invention provides processes and apparatuses for theeffective continuous production of reactant products, e.g., but notlimited to, liquid epoxy resins. In one embodiment of the presentinvention, a vertical continuous flow-through reactor system is providedwith a plurality of compartments one on top of the other. Reactants flowinto a first top compartment where reaction is initiated then by gravitythrough downcomers into intermediate compartments. Additional reactantsor catalyst or both may be added to any or all of the intermediatecompartments. The reaction may be allowed to proceed in the intermediatecompartments without the addition of more reactants to insure completereaction of the reactants. Liquid epoxy resins are discharged orwithdrawn from a bottom compartment.

In one embodiment epihalohydrin and an active hydrogen containingspecies are fed into an initial compartment and reacted with an alkalihydroxide to form a glycidyl ether of the active hydrogen containingspecies. An organic cosolvent may be added to enhance the solubility ofthe alkali salt of the active hydrogen containing species in the organicphase. By-product water formed in the reaction is codistilled withsolvent and a codistillate (of e.g. epichlorohydrin, solvent and water)is removed to maintain a desired concentration of water in thecompartment. The feed rate of the epihalohydrin and active hydrogencontaining species and the compartment size affect the extent of thereaction, i.e., the residence time.

Additional alkali hydroxide can be added to compartments below the topcompartment for further reaction. Additional compartments are used toinsure sufficient time for the reaction of the hydroxide. Theseadditional compartments, or "digestion stages" need not have anycatalyst added into them and the residence time in the additionaldigestion stages may be varied depending on the desired conversion ofproduct being produced.

Vapor or by-products may be removed from any or all compartmentssimultaneously by appropriate nozzles and outlets. Mixing impellers canbe provided in any compartment and in one embodiment are provided ineach compartment. By-product and water removal minimize yield losses tounwanted side reactions as does the co-addition of catalyst and reactantalkali hydroxide.

In order to prevent liquid leaking between stages, a liquid tight sealmay be used around the stirring shaft. The liquid seal may also be abearing or bushing for shaft support. One problem with this type of sealin epoxy resin manufacture is the abrasive nature of the by-productsalt. With this type of seal, the salt will migrate into the spacebetween the shaft and bushing or bearing and erode one of the matingsurfaces. The erosion will, with time, cause leakage betweencompartments and destroy the reaction residence time on the affectedstage. One method for eliminating this erosion problem is to elevate theseal above the liquid by means of a stand pipe. In one embodiment it ispreferred that the height of the stand pipes be greater than the heightof the downcomers carrying the liquid phase to the next lower reactionstage.

It is, therefore, an object of the present invention, to provide new,unique, efficient, effective, and nonobvious processes and apparatusesfor the continuous production of reactant products, e.g., but notlimited to liquid epoxy resins.

Another object of the present invention is the provision of suchprocesses in which a multi-compartment vertical reactor system isemployed.

Yet another object of the present invention is the provision of such aprocess and apparatus in which vapor containing reaction by-products,e.g. water, may be removed from some or all of the compartments,simultaneously if desired.

An additional object of the present invention is the provision of suchprocesses and apparatus in which catalyst and reactants can be added ina staged manner to any compartment to minimize yield losses.

A further object of the present invention is the provision of such aprocess and apparatus in which additional digestion stages are providedto insure sufficient time for the reaction, the residence times in thesestages variable as desired.

The present invention recognizes and addresses the previously-mentionedlong-felt needs and provides a satisfactory meeting of those needs inits various possible embodiments. To one of skill in this art who hasthe benefits of this invention's teachings and disclosures, other andfurther objects and advantages will be clear, as well as others inherenttherein, from the following description of presently-preferredembodiments, given for the purpose of disclosure, when taken inconjunction with the accompanying drawings. Although these descriptionsare detailed to insure adequacy and aid understanding, this is notintended to prejudice that purpose of a patent which is to claim aninvention no matter how others may later disguise it by variations inform or additions or further improvements.

DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features, advantages andobjects of the invention, as well as others which will become clear, areattained and can be understood in detail, more particular description ofthe invention briefly summarized above may be had by reference tocertain embodiments thereof which are illustrated in the appendeddrawings, which drawings form a part of this specification. It is to benoted, however, that the appended drawings illustrate preferredembodiments of the invention and are therefore not to be consideredlimiting of its scope, for the invention may admit to other equallyeffective equivalent embodiments.

FIG. 1 is a side schematic view in cross-section of a vertical reactorsystem according to the present invention.

FIG. 2 is a view along line 2--2 of FIG. 1.

FIG. 3 is a schematic view of flow in an apparatus according to thisinvention.

FIG. 4 is a schematic view of flow in an apparatus according to thisinvention.

FIG. 5A and 5B are side views of downcomers according to this invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

As shown in FIG. 1, a vertical reactor system 10 according to thepresent invention has a vessel 12 secured to a support flange 108, thevessel having a top feed inlet 20 for introducing reactant materials anda bottom discharge 18 for withdrawing products of the reaction of thereactant materials. The bottom head of the vessel is indicated bynumeral 114 and the top head by 116.

A plurality of reaction compartments are substantially verticallyaligned one on top of the other in the vessel 12, including a topcompartment 14, a bottom compartment 16, and intermediate compartments22, 24, 26, 30, 32, 34 and 36. Each compartment is defined by the sidesof the vessel 12 and stage plates 62 has a downcomer through whichmaterials flow into the next adjacent lower compartment, includingdowncomers 214 (for flow from the top compartment 14 to the next loweradjacent compartment 22); downcomers 42, 44, 46, 48, 50, 52, 54, 56; anddowncomer 216 in the bottom compartment 16 through which materialsincluding reaction products flow into a collection area 120 fordischarge through bottom discharge 18.

Any compartment may have an impeller for facilitating reactant materialmixing and the reaction of reactant materials to produce reactionproducts; but it is preferred that each compartment have a mixingimpeller. As shown in FIG. 1, each compartment has an impeller 70mounted on a common shaft 68 which extends through the vessel 12 fromtop to bottom and has its bottom end housed in a bearing 74. A stirringmotor 66 mounted on the top of the vessel 12 is connected to and rotatesthe shaft 68 and its connected impellers 70. The impellers 70 induce aradial component to the flow of materials in the compartments as shownin FIG. 3 in compartment 28. Such flow is desired because it has avelocity component directed through required cooling/heating coils toenhance transfer of heat and rapidly disperse catalyst or reactants.

For various other types of processes, different stirrers or impellersmay be preferable; e.g. in a process in which high shear and highemulsification is desired a turbine impeller may be used and in aprocess that is shear sensitive a marine impeller may be used.

Any compartment may have a vapor outlet nozzle, but it is preferred, asshown in FIG. 1 that each compartment have a vapor outlet nozzle 110.Vapor and vapor containing reaction products, by-products, orsub-products can be withdrawn through the vapor outlet nozzles on eachcompartment.

As shown in FIG. 2, each compartment may have (and it is preferred thatevery compartment have) a vapor outlet 110 (one shown for compartment24); a steam inlet 40 and a steam outlet 102 (one each shown forcompartment 24); a drain 80 and a drain valve 82 (one shown forcompartment 24); and an additional reactant or catalyst feed inlet 60(one shown for compartment 24). The drains 80 may serve as samplepoints.

The reactor system 10 is preferably used to produce liquid epoxy resinsand: epihalohydrins, for example, from the reaction between1,3-dihalo-2-propanol and/or 2, 3-dihalo-1-propanol and sodium hydroxide(the epihalohydrin being removed in vapor). Reactant materials, e.g. anexcess of epihalohydrin and an active hydrogen-containing species (e.g.bisphenol A) are fed into the top compartment 14 through top feed inlet20. Through an additional reactant feed inlet 60, catalyst and an alkalihydroxide (e.g. NaOH) is fed into the compartment. In the ensuingreaction, a glycidyl ether of the active hydrogen-containing species isformed along with various by-products and sub-products including waterand alkali salts.

The liquid reaction products, e.g. The liquid epoxy resin, reach aliquid level at the top of the downcomer 214 and flow by gravity throughthe downcomer 214 into the compartment 22 beneath the compartment 14.The extent of the reaction in the compartments (i.e., the residencetime) is affected by reactant feed rate, catalyst feed rate, downcomerheight, and compartment size.

In order to reduce the possibility of solid salt accumulating around thetop rim of the downcomer forming a dam which will retard the flow, anotch is provided in the downcomer rim to increase the flow velocity ofthe resin, salt and solvent mixture. If the production rates areincreased, then rather than deepening the notch, a multiple number ofnotches are provided. These notches are illustrated in FIG. 5A and 5B.As shown in FIG. 5A, a downcomer 300 has a body 302 with a notch 304 inthe top edge thereof. As shown in FIG. 5B, a downcomer 310 has a body312 with notches 314 in the top edge thereof.

To enhance the solubility of an alkali salt by-product of the activehydrogen containing species in the organic phase, an organic co-solvent(e.g. secondary alcohols, diethers, etc.) may be used, introduced intothe vessel with the reactant feed. By-product water formed in thereaction is co-distilled with this solvent and removed via the outlets110 to maintain the desired concentration of water in the compartments.Additional reactants, catalyst (e.g. NaOH), or both can be fed throughthe additional reactant or catalyst inlet 60 in each compartment. Forexample, in one process according to the present invention a process isprovided for the continuous preparation of liquid epoxy resins whichincludes contacting bisphenol A, epichlorohydrin and sodium hydroxide ina top compartment of a vertical reactor system as described herein;flowing reaction product and by-products of reaction of the bisphenol A,epichlorohydrin, and sodium hydroxide from the top compartment to atleast one more compartment and adding additional sodium hydroxide (orsodium hydroxide and either besphenol A, epichlorohydrin or both) to theone more compartment; agitating the reactant materials in thecompartments with an impeller rotatably mounted in the at least one morecompartment; (in one embodiment the impeller inducing radial flow of thereactant materials); introducing a solvent into the system and removingby product water from each compartment in a codistillate of theepichlorohydrin, solvent and water; withdrawing vapor reaction productsfrom each of the compartments; and withdrawing diglycidyl ethers ofdihydric phenols from a lower portion of the reactor system.

As shown in FIG. 3 mixing lines for the radial flow impeller 70 (shownby arrows) indicate circulation in the intermediate compartment 28. Theshaft 68 has a liquid seal 140 which minimizes leakage between adjacentcompartments. As shown in FIG. 4, a preferred liquid seal 140A iselevated above the liquid contents of the compartment 28 and above thetop edge of the downcomer 48. An elevated stand pipe 142 serves as amount for the seal 140A and also isolates the shaft 68 from thecompartment's liquid contents. The stand pipe 142 which is secured tothe stage plate 62 can be either open or sealed. To accommodate theliquid seal 140A, a support 69 extends from and is secured to the shaft68 to which are connected impeller blades 67 which rotate withoutcontacting the stand pipe 142 creating a liquid circulation pattern(shown by arrows) like that in FIG. 3.

"Digestion stages"--compartments into which no additional reactants arefed--may be employed to insure that all the alkali hydroxide has beenreacted. Residence time in the digestion stages may be varied asdesired. The co-addition of catalyst and reactant alkali hydroxide in astaged manner helps to minimize yield losses to unwanted side reactions,as does by-product water removed in the vapors.

Preferred embodiments of a reactor according to the present inventionmay be used in processes for producing liquid epoxy resins in which: thepreferred temperatures range between about 40° C. and about 100° C.;with pressures ranging between about 50 mm Hg and atmospheric pressure;water concentrations ranging between a about 0.2 weight percent andabout 6 weight percent (which is below the saturation limit of theliquid phase in the reactor), with an amount equal to or less than 2percent preferred; and bisphenol conversion rates ranging between about50% (e.g. for producing high molecular weight, low chloride contentepoxy resins) and up to almost 100%.

In conclusion, therefore, it is seen that the present invention and theembodiments disclosed herein are well adapted to carry out theobjectives and obtain the ends set forth at the outset. Certain changescan be made in the method and apparatus without departing from thespirit and the scope of this invention. It is realized that changes arepossible and it is further intended that each element or step recited inany of the following claims is to be understood as referring to allequivalent elements or steps for accomplishing substantially the sameresults in substantially the same or equivalent manner. It is intendedto cover the invention broadly in whatever form its principles may beutilized. The present invention is, therefore, well adapted to carry outthe objects and obtain the ends and advantages mentioned, as well asothers inherent therein.

What is claimed is:
 1. A process for the continuous preparation ofreaction product of the reaction of reactant materials, the processcomprisingcontacting the reactant materials for producing the reactionproduct in a top compartment of a vertical reactor apparatus, flowingreaction product and by-products of the reaction from the topcompartment of the reactor apparatus to at least one more compartment ofthe reactor apparatus and adding additional reactant materials to eachof the at least one more compartment for further reaction, agitating thereactant materials in each compartment, withdrawing vapor reactionproducts from each of the at least one compartment, and withdrawing thereaction product from a lower part of the reactor apparatus; and whereinsaid vertical reactor apparatus comprisesa vessel into which reactantmaterials for producing the reaction product flow and from which thereaction product and byproducts are withdrawn, the vessel divided by aplurality of plates into a plurality of intercommunicating compartmentsin substantially vertical alignment, including at least a top and abottom compartment each compartment having a top plate and a bottomplate, the reactant materials flowable from the top compartment, throughintermediate compartments, if any, and thence to the bottom compartmentsaid compartments having a vapor outlet for discharging vapor reactionproducts resulting from reactions in the compartments, said compartmentshaving a reactant inlet for introducing reactant materials into thecompartments, stirring means in at least one of the said compartmentsfor agitating the reactant materials therein, the vessel having inletmeans through which reactant materials are introduced into the topcompartment, the bottom compartment having discharge means through whichthe reaction product is withdrawn, the stirring means comprising arotatable shaft extending through the at least one compartment, theshaft extending sealingly through the compartment's bottom plate and topplate, a motor connected to the shaft exteriorly of the vessel forrotating the shaft and an impeller mounted on the shaft in the at leastone compartment.
 2. The process of claim 1 wherein the reaction productis diglycidyl ethers of dihydric phenols and said vertical reactorincludes a liquid-tight seal about the rotatable shaft in the at leastone compartment in which the impeller is mounted minimizing leakage fromthe at least one compartment.
 3. The process of claim 2 wherein thereactant materials are bisphenol A, epichlorohydrin, and an alkali metalhydroxide and wherein in said vertical reactor apparatus theliquid-tight seal is disposed above the liquid in the at least onecompartment and the impeller is spaced apart from the liquid-tight sealand wherein at least one catalyst inlet is provided in the vessel forfeeding catalyst into the top compartment and also includes a solventinlet for feeding a solvent into the first compartment.
 4. The processof claim 3 wherein a solvent is introduced into the vessel andby-product water is removed from each compartment in a codistillate ofthe epichlorohydrin, solvent and water and wherein said vertical reactorapparatus includes a solvent inlet for feeding solvent into eachcompartment.
 5. The process of claim 4 wherein water concentration inthe reactor system is maintained within a range of from about 0.2% toabout 6% weight percent.
 6. The process of claim 5 wherein the waterconcentration is maintained equal to or less than 2% weight percent. 7.The process of claim 1 wherein the temperature in the reactor system isbetween about 40° C. and about 100° C.
 8. The process of claim 1 whereinthe pressure in the reactor system is between about 50mm Hg andatmospheric pressure.
 9. A process for the continuous preparation ofliquid epoxy resins which comprisescontacting reactant materials forproducing the liquid epoxy resins in a top compartment of a verticalreactor apparatus, flowing reaction product and by-products of reactionof the reactant materials from the top compartment of the reactorapparatus to at least one more compartment of the reactor system andadding additional catalyst or reactant materials or both to the at leastone more compartment for further reaction. withdrawing vapor reactionproducts from each of the compartments, and withdrawing the liquid epoxyresins from a lower portion of the reactor apparatus, said verticalreactor apparatus comprisinga vessel into which reactant materials forproducing the reaction product flow and from which the reaction productand byproducts are withdrawn, the vessel divided by a plurality ofplates into a plurality of intercommunicating compartments insubstantially vertical alignment, including at least a top and a bottomcompartment, the reactant materials flowable from the top compartment,through intermediate compartments, if any, and thence to the bottomcompartment, each intermediate compartment having a top plate and abottom plate, said compartments having a vapor outlet for dischargingvapor reaction products resulting from reactions in the compartment,said compartments having a reactant inlet for introducing reactantmaterials into the compartment, a catalyst inlet for introducingcatalyst into the compartment and a solvent inlet for introducing asolvent into each compartment, stirring means in each of the saidcompartments, for agitating the reactant materials therein, the stirringmeans comprising a rotatable shaft extending through each intermediatecompartment's top plate and bottom plate with a liquid-tight seal aboutthe shaft in each intermediate compartment to inhibit liquid leakagebetween compartments, an impeller mounted to the rotatable shaft in eachcompartment, the vessel having inlet means through which reactantmaterials are introduced into the top compartment, and the bottomcompartment having discharge means through which the reaction product iswithdrawn.
 10. A process for the continuous preparation of liquid epoxyresins which comprisescontacting bisphenol A, epichlorohydrin and sodiumhydroxide in a top compartment of a vertical reactor apparatus, flowingreaction product and by-products of reaction of the bisphenol A,epichlorohydrin and sodium hydroxide from the top compartment of thereactor apparatus to at least one more compartment of the reactorapparatus and adding additional sodium hydroxide or sodium hydroxide andeither or both bisphenol A or epichlorohydrin to the at least one morecompartment for further reaction, agitating the reactant materials inthe compartments with an impeller rotatably mounted in the a least onemore compartment, the impeller inducing radial flow of the reactantmaterials, introducing into the apparatus a solvent and removing byproduct water from each compartment in a codistillate of the solvent andwater, withdrawing vapor reaction products from each of thecompartments, and withdrawing diglycidyl ethers of dihydric phenols froma lower portion of the reactor apparatus and wherein said verticalreactor apparatus comprisesa vessel into which reactant materials forproducing the liquid epoxy resins flow and from which the resultingliquid epoxy resins and by-products are withdrawn, the vessel divided bya plurality of plates into a plurality of intercommunicatingcompartments in substantially vertical alignment, including at least atop and a bottom compartment, the reactant materials flowable from thetop compartment, through intermediate compartments, if any, and thenceto the bottom compartment, each intermediate compartment having a topplate and a bottom plate, said compartments having a vapor outlet fordischarging vapor reaction products resulting from reactions in thecompartment, said compartments having a reactant inlet for introducingreactant materials into the compartment, stirring means in eachcompartment for agitating the reactant materials therein, the stirringmeans comprising a rotatable shaft sealingly extending through thecompartments, a motor connected to the shaft exteriorly of the vesselfor rotating the shaft, and an impeller in each compartment secured tothe shaft, the impeller inducing radial flow in the reactant materials,a liquid-tight seal above the shaft in each intermediate compartment toinhibit liquid leakage between compartments, the vessel having inletmeans through which reactant materials are introduced into the topcompartment, the bottom compartment having discharge means through whichthe liquid epoxy resins produced by the reactions in the compartmentsare withdrawn, a catalyst inlet communicating with each compartment forfeeding catalyst into each compartment, and a solvent inletcommunicating with each compartment for feeding a solvent into eachcompartment.
 11. The process of claim 10 wherein liquid flows from onecompartment into a next compartment underneath it through a downcomermounted in the one compartment.
 12. The process of claim 11 wherein theliquid-tight seal is disposed above a top end of the downcomer in eachcompartment to inhibit contact of the seal by liquid in thecompartments.